Speaker
Description
As highly energetic physics laboratories, blazars are prime candidates to reveal the mysteries of the most energetic parts of our universe. For many of them, the very-high-energy (>0.2 TeV, VHE) γ-ray band as well as the X-ray bands are especially interesting since they host the most variable part of their emission.
We present a multiwavelength (MWL) data set of Mrk 501 obtained from 2017 to 2020 revealing a historically low activity in exactly these bands. Using the comprehensive VHE data set collected by the two MAGIC telescopes, we can identify a low-state lasting for two years with a stable and historically low VHE flux (>0.2 TeV) of 5% that of the Crab Nebula. We use this unprecedented opportunity to investigate, additionally using constraints set by public IceCube data, the nature of the low-state which can be attributed to the MWL emission of leptonic, lepto-hadronic as well as purely hadronic scenarios. This potential baseline emission can be explained by a standing shock while the more variable emission before the low-state can be connected to an additional traveling shock region. The patterns appearing in this variable emission show a significant correlation between VHE γ-rays and X-rays for the first time also during low activity states for Mrk 501. Extending the data set to 12 years, we identify several significant correlations, such as a correlated behavior between HE γ-rays and X-rays supporting a common origin between these bands and the claim that the variable emission originates from relativistic leptons.
| Collaboration name | for the Multi-wavelength collaborators and the MAGIC and Fermi-LAT-Collaboration |
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